DE102012219857B4 - Crane with mobile counterweight unit - Google Patents

Abstract

Crane (10) with:
a lower body (15);
an upper pivot body (20) mounted on the lower body (15) so as to be pivotable;
a counterweight unit (30) having a plurality of wheels (40) each capable of rolling on the ground (G) and having a variable steering angle (θ), the counterweight unit (30) being able to roll on the ground (G) with respective rolling movements of the wheels (40) in a rotational direction which is equal to a pivoting direction of the upper pivoting body (20) to drive in a state in which it depends from the upper pivoting body (20);
a steering actuator (50) adapted to rotate the wheels (40) about a steering axis of rotation to change their steering angle (θ);
and a steering control device (80; 201) for controlling an operation of said steering actuator (50), said steering control device (80; 201) comprising a swivel identification signal receiving section (81) receiving a swivel identification signal for identifying a swivel direction of said upper swivel body (20). and having an actuator operating portion (80a) that operates the steering actuator (50) based on an orbit of the counterweight unit (30) and the swivel direction identified by the swivel identification signal so as to make a line along the traveling direction of the wheels (40) is that it is inclined inwardly to a tangent line which is arranged on the Lenkdrehmittelachse of the wheels (40), wherein the tangent line tangent to the orbit of the counter-rotating in the direction of rotation counterweight unit (30) is when the upper swinging body (20) pivots so that driving of the counterweight unit (30) in the rotating direction is involved.

Description

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a crane equipped with a unit having a plurality of wheels and capable of traveling on the ground in one direction of rotation.

Description of the background of the prior art

Heretofore, a crane equipped with a traveling counterweight unit has been known, for example, as described in the following patent documents: JP 2 895 434 B2 . JP 2 895 437 B2 and JP H02-5 665 B2. This counterweight unit, for example, depends on a mast of the crane. In this state, by accompanying a swinging movement of an upper swinging body of the crane, the counterweight unit can travel on the ground with respect to a direction of the swinging motion. In addition, in a situation where the crane is operated to lift a suspended load having a predetermined mass or more, the counterweight unit floats from the ground.

In many cases, the above-mentioned type of counterweight unit is connected to the upper swivel body of the crane by a connecting member. In an in 9B The example shown is the counterweight unit 90 through a connecting element 92 with an upper swivel body 91 a crane connected, in particular, it is connected to the connecting element 92 connected by a pin so that it is tiltable with respect to the ground. In another in 9C The example shown is the counterweight unit 90 by two connecting elements 92 with the upper swivel body 91 connected to two positions, an upper and a lower position, thus preventing inclination to the ground is prevented. Alternatively, some cases may occur where the counterweight unit 90 not directly with the upper swivel body 91 connected is.

Each of the aforementioned counterweight units is provided with a plurality of wheels whose orientation is set in a direction aligned with a tangent line to a rotational direction of the wheel; however, in reality, a turning radius of the wheel of the counterweight unit increases, and it is likely that various disadvantages are brought about. In particular, as in 9A is shown in the conventional counterweight unit, although the orientation of each of the wheels 94 (a forward and backward direction of the wheel) is set to be with a tangent line L1 to an orbit (a track) C of the wheel 94 matches an actual position of the wheel 94 from the normal orbit C to the outside, that is, a circular trajectory having a radius R due to a centrifugal force acting on the counterweight unit traveling in a rotating direction, resulting in an inappropriate increase of a turning radius of the wheel 94 brings with it. The increase of the turning radius causes the following disadvantages.

First, in the case where the counterweight unit is not directly connected to the upper swing body, the counterweight unit is normally disposed immediately below a distal end of a pylon; however, increasing the radius of rotation of the wheel increases a turning radius of the entire counterweight unit, thus offsetting the counterweight unit to the rearward facing side with respect to the upper pivoting body from the position below the distal end of the mast. In this state, when the crane lifts a suspended load having a predetermined mass or more to thereby make the counterweight unit float up from the ground, i. h., to lift the restriction of the counterweight unit by the friction with the ground, the counterweight unit returns to a position immediately below the distal end of the mast, i. H. to a position corresponding to the normal turning radius r due to the gravity applied to the counterweight unit. This causes the counterweight unit to swing in a direction of the turning radius.

Second, in the case of the counterweight unit 90 passing through the connecting element 92 with the upper swivel body 91 is connected, as in the 9B and 9C shown is the increase in the radius of rotation of the wheel 94 not the turning radius r of a unit body of the counterweight unit 90 vary; this case involves the following drawback: in the case of the tilting counterweight unit 90 who in 9B is shown increases the increase of the turning radius r of the wheel 94 not the turning radius r of the unit body of the counterweight unit 90 what a difference between the turning radius of the unit body of the counterweight unit 90 and the turning radius of the wheel 90 arise, this difference undesirably the entire counterweight unit 90 inclines. Especially in the case where the wheel 94 is easily deformable, such as a pneumatic tire, ie, a tire used in an air-filled state, the inclination of the entire counterweight unit increases 90 even more. The inclination of the counterweight unit 90 causes the respective on the wheels 94 applied Loads become non-uniform, causing the wear of the wheel 90 is accelerated and the life of the wheel is shortened. On the other hand, in the case where the counterweight unit 90 is not inclinable, as is in 9C shown is the increase in the radius of rotation of the wheel 90 that the wheel 94 a significant gravity, whereby the wheel 94 is brought to an abnormal deformation. Consequently, in this case, damage and wear of the wheel 94 accelerated, resulting in a shortened life of the wheel.

As a measure for avoiding the above-described disadvantages, it is conceivable to carry out an operation in which the turning radius of the wheel returns to an appropriate value, for example, an operation for changing the orientation of the wheel from that in FIG 9A shown state under linear movement of the counterweight unit 90 to an inwardly facing side of the orbit (track) C, after which the orientation of the wheel in the in 9A shown state returns again; however, this operation is complicated and time consuming, causing a deterioration in the efficiency of crane operations.

The DE 20 2009 011 577 U1 discloses a crane with a lower body; an upper pivot body pivotally mounted on the lower body; and a ballast wagon with a variety of wheels. The ballast can be connected via a coupling element with the upper pivot body.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a crane equipped with a counterweight unit having a plurality of wheels capable of traveling on the ground in one direction of rotation, the crane being capable of doing so To avoid increasing the turning radius of the wheels to improve the operating efficiency of the crane.

This object is achieved by a crane having the features of claim 1. Advantageous developments are the subject of the dependent claims.

list of figures

• 1 shows an overall view of a crane according to an embodiment of the present invention.
• 2 shows a plan view in which mainly an upper swivel body and a counterweight unit of the crane of 1 are shown.
• 3 shows a block diagram of a steering control device of the crane according to the first embodiment.
• The 4A and 4B show schematic plan views of a plurality of wheels of the counterweight unit of in 1 shown crane.
• 5A shows a plan view as a pair of provided wheels of the counterweight unit.
• 5B FIG. 11 is a side view of the wheels provided as a pair as viewed in a wheel-axis direction. FIG.
• 6 shows a block diagram of a steering control device according to a second embodiment of the present invention.
• 7 shows a block diagram of a steering control device according to a third embodiment of the present invention.
• 8th shows a block diagram of a steering control device according to a fourth embodiment of the present invention.
• 9A shows a plan view of a driving trajectory of a counterweight unit of the prior art.
• The 9B and 9C show front views of a deformation of a wheel due to an increase of the radius of rotation of the wheel in the counterweight unit of the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the 1 to 5A and 5B A first embodiment of the present invention is described. The 4A and 4B show schematic plan views of a plurality of wheels of a counterweight unit 30 according to the first embodiment in respective situations where the counterweight unit 30 so that it rotates clockwise and counterclockwise, in a plan view.

1 shows a crane 10 that with the counterweight 30 Is provided. This crane 10 is a cargo handling machine for lifting a suspended load, and may be, for example, a traveling crane or a grid boom crawler crane.

The crane 10 has the following: a lower body 15 ; and an upper swivel body 20 that swivels on the lower body 15 is mounted and a swivel frame 24 , a boom 21 , a first mast 22 and one second mast 23 having; a counterweight unit 30 coming from the upper swivel body 20 for example, from the first mast 22 of the upper pivoting body 20 hanging (hung on); and a steering actuator 50 and a steering control device 1 , each in 3 are shown. The steering actuator 50 is operated to provide a steering angle of the counterweight unit 30 changes, and the steering control device 1 actuates the steering actuator 50 such that driving of the counterweight unit and in particular its steering angle is controlled.

The lower body 15 is a section for driving the crane 10 ; ie, a lower body equipped with a drive, for example, a in 1 shown chain (bead) or a plurality of wheels. The swiveling frame 24 of the upper pivoting body 20 is on the lower body 15 mounted so that it is about a vertical pivot axis O1 , in the 2 is shown, is pivotable, and the boom 21 , the first mast 22 and the second mast 23 are on the hinged frame 24 fixed in a liftable and lowerable manner, in this order from a front of the pivotable frame 24 are arranged from. The boom 21 is a structural element for suspending a load by a wire rope and has, for example, a grid structure. The first mast 22 is a structural element for lifting and lowering the boom 21 by a wire rope or an anchoring line and has for example a grid structure. The second mast 23 is an element for lifting and lowering the first mast 22 by an anchoring line or the like and has, for example, a box-shaped structure.

The counterweight unit 30 is a dead weight element for canceling a gravitational torque (gravitational moment) that is caused by a crane 10 attached load acts, with the moment intending the crane 10 lean forward to a lifting capacity of the crane 10 to improve. The counterweight unit 30 is from a distal end of the first mast 22 through a hanging rope 31 suspended and adapted to touch the ground G when the boom 21 attaches a load having a mass less than a predetermined value (including a situation in which no load is suspended), and floats from the bottom G when the mass of the suspended load is equal to or greater than the predetermined value is.

The counterweight unit 30 is able to drive on the floor G, with the pivoting of the upper slewing body 20 in relation to the lower body 15 is accompanied in a rotational direction that corresponds to the direction of pivoting, while the ground G is touched (seated), as described below. More specifically, the counterweight unit 30 a unitary body 35 and a variety of wheels 40 on, on the unit body 35 are rotatably mounted. The wheels 40 are adjusted to roll on the ground G to driving the counterweight unit 30 to enable.

The counterweight unit 30 is with the upper swivel body 20 by a unit body connector 32 connected. The unit body connector 32 connects the counterweight unit 30 (more precisely, the unitary body 35 ) and the upper swivel body 20 with each other to keep a distance between them constant or approximately constant. The unit body connector 32 can, for example, like this in 2 is shown, of two rod-shaped elements 32a consist of each of a right and left side surface of the upper pivot body 20 to a rearward facing side with respect to the upper die body 20 protrude, like this in 2 or it may be a rod-shaped member or an element of any suitable shape other than a rod shape. The unit body connector 32 and the unitary body 35 For example, as in 1 is shown to be interconnected at a single position by means of a pin connection so as to allow the unitary body 35 is inclined to the floor G, or at least at an upper and a lower position by means of a pin connection may be connected to each other so that it is excluded that the unit body 35 sloping towards the bottom G, as for example in 9C is shown. Alternatively, the unit body connector 32 be omitted.

Each of the wheels 40 is formed of a rubber tire used in an air-filled state, ie, a pneumatic tire, and is rotatable on the unit body 35 so fastened that it allows the counterweight unit 30 in one direction of rotation. The wheels 40 are at respective positions, for example, four positions, as in the 4A and 4B is shown at a lower end portion of the unit body 35 intended. The wheels 40 are preferably in a plurality of rows (for example, FIG 1 three rows and show the 4A and 4B two rows) arranged in the forward and backward direction of the upper slewing body 20 are aligned, as in 2 that is, in a direction approximately along the swing radius r, and they are in a plurality of rows (for example, FIGS 4A and 4B two rows) in a width direction of the upper swing body 20 aligned, ie, in a direction approximately along a rotational C, which will be described in more detail below. The following description refers to the arrangement the wheels 40 like this in the 4A and 4B is shown, except where specifically mentioned.

The in the forward and backward facing direction of the upper pivot body 20 arranged wheels 40 are adapted to be steered around a common vertical steering central axis O2 be turned in one piece. Besides, the wheels can 40 also be designed so that they are individually steered. Alternatively, three or more of the wheels 40 be guided in one piece.

The steering actuator 50 is on the unit body 35 fastened while he is with each of the wheels 40 connected to the wheels 40 around the steering turning center O2 to turn so that a steering angle θ of the wheel 40 will be changed. The steering actuator 50 According to the first embodiment, a hydraulic actuator that is operable to be actuated by a hydraulic pressure from a hydraulic pressure source 51 is driven, which is formed for example of a hydraulic cylinder or a hydraulic motor.

The steering control device 1 is designed to be the steering actuator 50 operated so that the steering angle θ of the wheels 40 on the basis of a pivoting direction of the upper pivoting body 20 is controlled, as indicated by the arrows in the 4A and 4B is shown. What the steering control device 1 As far as all components or elements of this can be within the counterweight unit 30 be incorporated, or a part of the components or elements in other places, such as the upper swivel body 20 be installed.

Like this in 3 is shown, the steering control device 1 on: a hydraulic pressure source 51 for supplying a hydraulic pressure to the steering actuator 50 , a selector valve 52 that is between the hydraulic pressure source 51 and the steering actuator 50 is arranged, a calculation and control unit 80 that with the selector valve 52 connected to the selector valve 52 to operate, and a steering angle sensor 72 which is operable to control the steering angle θ of the wheel 40 detected.

In the first embodiment, the steering angle θ is an angle that is between a tangent line L1 to a circular orbit C of the counterweight unit 30 like this in the 4A and 4B is shown, and a so-called half-line L2 is defined, extending from the Lenkdrehmittelachse O2 to a forward-facing side of the wheel 40 along the forward and backward direction of the wheel 40 extends. The steering actuator 50 performs its operation depending on the selected position of the selector valve 52 so that the steering angle θ of the wheel 40 is changed or it stops the operation.

The selector valve 52 having a plurality of positions to be selected is adapted to the operation of the steering actuator 50 in the change of its selected position by an electric signal (or a hydraulic pressure signal or the like) to switch, that of the calculation and control device 80 is entered. More precisely, the selector valve shuts off 52 allowing / preventing the delivery of the hydraulic fluid from the hydraulic pressure source 51 to the steering actuator 50 and switches a direction of delivery.

The steering angle sensor 72 may be of a kind for directly detecting the steering angle θ of the wheel 40 or may be of a type for detecting a parameter on the basis of which the steering angle θ is calculated, such as an extension retracting position or a rotational position of the steering actuator 50 , The steering angle sensor 72 generates a steering angle signal that is a signal about information indicating the steering angle θ or an equivalent value to the steering angle θ, and the steering angle signal to the computing and control unit 80 enters.

The calculation and control unit 80 is configured to receive respective input signals from various information signals and the operation of the steering actuator 50 based on the received signals. The calculation and control unit 80 can in the in 1 shown counterweight unit 30 be installed or it may be in another location such as in the upper pivoting body 20 be installed.

The calculation and control unit 80 includes: a calculation section 80a , a pan identification signal receiving section 81 a swivel angle signal receiving section 82 and a target steering angle storage section 83 like this in 3 is shown. The pan identification signal receiving section 81 receives a pan identification signal for identifying the pan direction of the upper pan body 20 (in the 4A direction shown or in 4B shown direction). The swivel identification signal according to the first embodiment is provided by the upper swivel body 20 and the pan identification signal receiving section 81 is with the upper swivel body 20 connected by an electrical line to receive the pan identification signal. The swivel identification signal, that is, a signal for identifying the swivel direction of the upper swivel body 20 , may be an electrical signal based on a Hebelbetätigens by a user of in 1 shown crane 10 is generated, or is converted from a hydraulic signal based on the lever operation, or it may be an electric signal that is from a hydraulic pressure for driving a hydraulic motor for pivoting the upper pivot body 20 is converted. The steering angle signal receiving section 82 receives the steering angle signal generated by the steering angle sensor 72 is generated, that is, an information signal indicating information about an actual steering angle θ of the wheel. What the steering angle θ of the wheel 40 As far as the target steering angle storage section stores 83 in this one target steering angle θ ₀ , which is a "proper steering angle" corresponding to each of the swing directions of the upper swing body 20 is predetermined.

The steering control device 1 performs the following operation. The calculation and control unit 80 controls the steering actuator 50 such that the actual steering angle θ of the wheel 40 in accordance with the target steering angle θ ₀ in the target steering angle storage section 83 stored is brought. More precisely, the calculation and control unit controls 80 the operation of the steering actuator 50 who in 3 is shown, so that the wheel 40 to the inside of the tangent line L1 to the orbit C of the wheel 40 at the position of the wheel 40 is aligned in plan view, as shown in the 4A and 4B is shown.

The details of the operation are described below. When the lever is actuated by the user of the in 1 shown crane for pivoting the upper pivot body 20 becomes the swivel identification signal, that is, an electrical signal that provides information for enabling the actual swivel direction of the upper swivel body 20 is identified from the upper swivel body 20 in the pan identification signal receiving section 81 entered, like this in 3 is shown. The calculation section 80a reads from the target steering angle storage section 83 the target steering angle θ ₀ associated with the pan direction identified on the basis of the pan identification signal provided by the pan identification signal receiving section 81 Will be received. At the same time, the steering angle signal generated by the steering angle sensor 72 is generated, that is, a detection result on the actual steering angle θ of the wheel 40 , in the calculation section 80a via the steering angle signal receiving section 82 entered. The calculation section 80a gives to the selector valve 52 a command to switch the selected position of the selector valve 52 in such a manner that the actual steering angle θ is brought into correspondence with the target steering angle θ ₀ . As the steering actuator 50 depending on the selected position of the selector valve 52 is operated to change the steering angle θ of the wheel, the calculating section 80a Control the steering angle θ by the selected positions of the selector valve 52 be switched. The calculation section 80a thus has an "Aktuatorbetätigungsabschnitt", the steering actuator 50 operated, with a selector valve 52 is installed. The change of the steering angle θ becomes concurrent with the pivoting of the upper swing body 20 and the ride of the counterweight unit 30 in the direction of swinging. If the actual steering angle θ of the wheel matches 40 with the target steering angle θ ₀ holds the calculation and control unit 80 the actuation of the steering actuator 50 at.

The time to start swinging the upper swivel body 20 and the timing for starting and ending the change of the steering angle θ of the wheel 40 can be determined differently. For example, the change of the steering angle θ of the wheel 40 are started following the pivoting of the upper swivel body 20 , It is also possible with the actual pivoting of the upper pivoting body 20 in accordance with the steering angle θ of the wheel 40 to begin with the target steering angle θ ₀ .

More specifically, the calculation and control unit operates 80 the steering actuator 50 so that the wheel 40 to the inside of the tangent line L1 to the orbit C of the wheel 40 at the position of the wheel 40 is aligned, that is more precisely at the position of the Lenkdrehmittelachse O2 of the wheel 40 in plan view, as shown in the 4A and 4B is shown, preferably so that all wheels 40 attached to the counterweight unit 30 are provided, meet the above-mentioned condition. In this condition, the "position of the steering center axis means O2 of the wheel 40 "following: in the case where the two or more wheels 40 (in the 4A and 4B : the two wheels 40 ) in one piece about a common Lenkdrehmittelachse O2 are rotated, the position corresponds to the Lenkdrehmittelachse O2 a position of the common Lenkdrehmittelachse O2 the wheels; in the case where the two or more wheels 40 individually steered, corresponds to the position of the steering center axis O2 a steering central axis for each of the wheels. In addition, the "orbit C of the wheel 40" means a circle having a center at the pivot center axis O1 of the upper pivoting body 20 according to 2 passing through the steering axis of rotation O2 occurs, ie a circular orbit. Incidentally, a line segment corresponding to the pivot center axis O1 and the pivot axis of rotation O2 connects to each other, the turning radius r of the wheel 40 , The wheel 40 is at the inside of the tangent line L1 aligned "means that a front section of the wheel 40 in its forward and backward direction (a front side of the wheel 40 approximately in its direction of travel) to the pivot axis O1 in relation to the tangent line L1 aligned, ie the half-line L2 is to the pivot axis O1 in relation to the tangent line L1 aligned.

A specific value of the target steering angle θ ₀ is determined on the basis of previous examinations and studies. For example, it is possible to perform an experiment and an analysis to find out the steering angle θ that allows the turning radius r of the wheel 40 is held constant regardless of a centrifugal force acting on the counterweight unit during the rotation of the counterweight unit 30 acts and that the found angle θ is set as the target steering angle θ ₀ . The experiment and the analysis are preferably carried out under the condition of a non-suspended load, ie a condition of a maximized load imposed on the wheel 40 is imposed. The target steering angle θ ₀ may be, for example, based on a ground contact length Lc of the wheel 40 according to 5B be determined. The ground contact length Lc is a length in the front and rear direction of the wheel 40 from a section of the wheel 40 which is in contact with the bottom G. For example, the target steering angle θ _{0 is set} to a smaller value as the ground contact length Lc becomes larger. More specifically, in an in 5A shown plan view of the target steering angle θ _{0 are set} in the following manner.

Defining a first reference point P1

Like this in 5A is shown, a point that is on the tangent line L1 lies and in front of the Lenkdrehmittelachse O2 of the wheel 40 in the forward and backward direction of the wheel 50 by a distance from "coefficient a" x "ground contact line Lc", as a first reference point G1 established. The coefficient a can be set to various values, for example, in the range of 1.3 to 1.5 or 1.5.

Setting the auxiliary line L3

A straight line parallel to the tangent line L1 and spaced from the tangent line L1 is a distance B inward from the orbit C, as shown in the 4A and 4B is shown as an auxiliary line L3 established. The distance B is a certain length based on an arrangement of the plurality of wheels 40 , the dimensions of each of the wheels 40 etc. is determined. For example, in the case of integrally steering the two wheels 40 around the steering turning center O2 as the distance B, a distance between the Lenkdrehmittelachse O2 and a middle O3 from one of the wheels 40 set on the inside of the orbit C in plan view.

Setting the second reference point P2

An intersection between a straight line L4 and the auxiliary line L3 is as a second reference point P2 set, with the line L4 through the first reference point P1 occurs and perpendicular to the tangent line L1 crosses.

Setting the target steering angle θ ₀

A steering angle that allows the half-line L2 extending from the steering axis of rotation O2 of the wheel 40 to a forward facing side in the forward and backward direction of the wheel 40 extends through the second reference point P2 is set as a target steering angle θ ₀ . For example, a specific value of the target steering angle θ _{0 is set} in the range of 0.5 to 1.5 degrees or 1 degree. 5A shows the wheels 40 in such a position that its forward and backward direction is parallel to the tangent line L1 is, ie the wheels 40 before the correction of the steering angle θ by the solid line, and shows the wheel 40 after correcting the steering angle θ using the two-dot chain line.

The device described above is capable of preventing the turning radius r of the wheel 40 greater than a normal radius of rotation during a counter-unit rotation movement 30 is determined by the steering angle θ of each of the wheels 40 so controlled that the half line L2 that an alignment of the wheel 40 to the inside of the tangent line L1 points to which orbit C is aligned, thus avoiding the disadvantages due to an increase in the turning radius. Incidentally, it is possible to eliminate or simplify an operation for restoring the increased turning radius R to its original state, thereby improving the operating efficiency of the crane 10 is possible.

1. (a) In dem Fall, bei dem die Gegengewichtseinheit 30 mit dem oberen Schwenkkörper 20 durch das Einheitskörperverbindungselement 32 so verbunden ist, dass sie zu dem Boden G neigbar ist, wie dies in 1 gezeigt ist, kann die Neigung der Gegengewichtseinheit 30 in Bezug auf den Boden G aufgrund der Zunahme des Drehradius r vermieden werden. Dies ermöglicht ein Vermeiden eines Ungleichgewichts der jeweiligen Lasten, die auf die Räder 40 aufgebracht werden, oder einer Verformung des Rades 40 aufgrund der Neigung, was zu einer verbesserten Lebensdauer des Rades 40 führt.
2. (b) In dem Fall der Gegengewichtseinheit 30, die mit dem oberen Schwenkkörper 20 durch das Einheitskörperverbindungselement 32 verbunden ist, um so auszuschließen, dass die Gegengewichtseinheit 30 sich zu dem Boden G beispielsweise in dem Fall neigt, bei dem die Verbindung durch die Verwendung einer Vielzahl an Elementen erreicht wird, die Seite an Seite in einer nach oben und nach unten weisenden Beziehung angeordnet sind, wie dies in 9C gezeigt ist, kann die Verformung des Rades 40 aufgrund der Zunahme des Drehradius vermieden werden. Folglich kann auch in diesem Fall die Lebensdauer des Rades 40 verbessert werden.
3. (c) In dem Fall, bei dem die Gegengewichtseinheit 30 nicht direkt mit dem oberen Schwenkkörper 20 verbunden ist, kann verhindert werden, dass die Gegengewichtseinheit 30 in einer Richtung des Drehradius schwingt, wenn die Gegengewichtseinheit 30 von dem Boden G unter einer Bedingung eines erhöhten Drehradius der Gegengewichtseinheit 30 aufschwimmt.

More specifically, avoidance of an increase in the rotational radius r of the wheel 40 the following advantageous effects.

1. (a) In the case where the counterweight unit 30 with the upper swivel body 20 through the unit body connector 32 is connected so that it is tiltable to the ground G, as in 1 can be shown, the inclination of the counterweight unit 30 with respect to the ground G due to the increase of the turning radius r are avoided. This allows avoidance of imbalance of the respective loads acting on the wheels 40 be applied, or a deformation of the wheel 40 due to the inclination, resulting in improved life of the wheel 40 leads.
2. (b) In the case of the counterweight unit 30 that with the upper swivel body 20 through the unit body connector 32 is connected so as to preclude the counterweight unit 30 for example, in the case where the connection is achieved by the use of a plurality of members arranged side by side in an up-and-down relationship, as shown in FIG 9C can be shown, the deformation of the wheel 40 due to the increase in the radius of rotation can be avoided. Consequently, in this case too, the life of the wheel 40 be improved.
3. (c) In the case where the counterweight unit 30 not directly with the upper swivel body 20 can be prevented, the counterweight unit 30 swings in one direction of the turning radius when the counterweight unit 30 from the ground G under a condition of increased turning radius of the counterweight unit 30 floats.

In addition, the calculation and control unit 80 according to the in 3 shown first embodiment, the target steering angle storage section 83 which stores therein a target steering angle θ ₀ which is considered to be an appropriate angle of the wheel 40 corresponding to each pivoting direction of the upper pivoting body 20 is predetermined, and adapted to the steering actuator 50 so that the actual steering angle θ of the wheel 40 is matched with the target steering angle θ ₀ , perform control that is simplified and improved in view of a response speed of the steering control of the wheel as compared with the case where an appropriate steering angle θ of the wheel 40 during a turn on a real time basis.

Incidentally, the signal included in the pan identification signal receiving section has 81 the calculation and control unit 80 is input, the one of the upper pivot body 20 output electrical signal is an advantage in that it is applicable to an embodiment of a structure in which none of the wheels 40 is driven in rotation, as for example in the third embodiment, which is described below.

Below is a steering control device 101 according to a second embodiment of the present invention with reference to 6 described. While the steering control device 1 of in 3 shown first embodiment, the steering angle of the wheel 40 controls when a signal to pivot the upper pivot body 20 in the calculation and control unit 80 is input, is the steering control device 101 of the second embodiment is constructed so that it the steering angle of the wheel 40 controls when increasing the turning radius r of the wheel 40 is detected. This difference is described in more detail below. In the second embodiment and in the third and fourth embodiments described below, the lower body becomes 15 , the upper swivel body 20 , the counterweight unit 30 and the steering actuator 50 , each at the crane 10 According to the first embodiment, are used as common components, and therefore omitted their re-description in the embodiments explained below.

Like this in 6 is shown has the steering control device 101 according to the second embodiment, a load sensor 74 and a tilt sensor 76 in addition to the steering angle sensor 72 of the first embodiment. The steering control device 101 has a calculation and control unit 80 comprising a load signal receiving section 84 , a storage section 85 for an allowable load distribution, a tilt angle signal receiving section 86 and a storage section 87 for an allowable inclination angle in addition to the calculating portion 80a , the pan identification signal receiving section 81 , the steering angle signal receiving section 82 and the target steering angle storage section 83 of the first embodiment.

The load sensor 74 is designed to capture a load on each of the wheels 40 the counterweight unit 30 is applied, and is for example on a not graphically shown suspension device for the wheel 40 built-in. The load sensor 74 is so operable that he gets one on the bike 40 applied load on the basis of a hydraulic pressure of a damper, which is included in the suspension device, or an expansion amount (expansion amount) of the damper or a spring, which is included in the suspension device detected. The load signal receiving section 84 receives a signal from the load sensor 74 is output, that is, an information signal indicative of a load on each of the wheels 40 is applied, and outputs the received signal to the calculating section 80a one. The storage section 85 for the allowable load distribution stores therein a predetermined allowable value of a load distribution nonuniformity degree, which is a degree of nonuniformity among the respective loads applied to the wheels 40 applied, indicates. The details of Load distribution nonuniformity are described below.

The tilt sensor 76 is operable to have a tilt angle of the unitary body 35 the counterweight unit 30 detects, in particular an inclination angle of the unit body 35 with respect to a normal line to the ground G. The tilt angle signal receiving section 86 receives a signal from the tilt sensor 76 is output, that is, an information signal indicating the inclination angle of the counterweight unit 30 indicates and inputs the received signal to the calculating section 80a one. The storage section 87 for the allowable inclination angle stores in this a predetermined allowable value on the inclination angle of the counterweight unit 30 ,

Below is an operation of the steering control device 101 of the second embodiment, and in particular, a calculation process performed by the calculating section 80a the calculation and control unit 80 is performed.

Control based on the load distribution nonuniformity

When the turning radius r of the wheel 40 is increased in an effected rotation of the counterweight unit 30 , in the 1 shown is the counterweight unit 30 raised inwards, for example similar to the counterweight unit 30 , in the 9A is shown, so that the respective loads acting on the wheels 40 be applied to a non-uniformity. Consequently, it is effective, the steering angle θ of the wheel 40 to control on the basis of a degree of nonuniformity of the loads.

In this regard, the calculation section is 80a the calculation and control unit 80 so constructed that it has a load distribution nonuniformity degree, which has a degree of nonuniformity among the respective ones on the wheels 40 indicates applied loads, based on the load signal from the load sensor 74 via the load signal receiving section 84 is inputted, calculated, and then compares the calculated load distribution nonuniformity degree with the allowable value of the load distribution nonuniformity degree. More specifically, the load distribution nonuniformity degree can be obtained, for example, by taking a difference between a maximum value and a minimum value of the respective ones on the wheels 40 applied loads, or by a difference between an average value of the loads of all wheels 40 and the load from any wheel of the wheels 40 in relation to each of the wheels 40 is calculated and the sum of the resulting differences is calculated. Simultaneously with the calculation explained above, the calculating section reads 80a the allowable value of the load distribution irregularity degree in the storage section 85 is stored for the allowable load distribution to compare the read allowable value with the calculated actual load distribution nonuniformity degree, and controls the steering actuator 50 according to the resulting difference. More specifically, in the case where the actual load distribution nonuniformity degree is equal to or less than the allowable value, the calculation and control unit performs 80 a control in which the steering angle θ is kept at zero degrees, that is, it performs a control in which an alignment of each of the wheels 40 in the forward and backward direction with the orientation of the tangent line L1 of the orbit C is brought into agreement (see 4 ); wherein, in the case where the actual load distribution nonuniformity degree is greater than the allowable value, the calculation and control unit 80 performs a control in which the steering angle θ of the wheel 40 is corrected, for example, wherein the steering angle θ is corrected to the target steering angle θ ₀ , which is a predetermined appropriate steering angle.

Control based on the angle of inclination

Because the counterweight unit 30 during the increase of the turning radius r of the counterweight unit 30 , in the 1 As shown above, it is also effective to control the steering angle θ of the wheel 40 based on a tilt angle of the counterweight unit 30 to control.

In this regard, the calculation section is 80a designed so that an actual inclination angle of the counterweight unit 30 which is obtained on the basis of a signal coming into it from the tilt sensor 76 about the inclination angle signal receiving section 86 is input with the allowable value of the inclination angle included in the memory section 87 is stored for the allowable inclination angle is compared and the steering actuator 50 is controlled according to the resulting difference. More specifically, in the case where the actual inclination angle is equal to or less than the allowable value, the calculation and control unit performs 80 a control in which the steering angle θ is kept at zero degrees, that is, it performs a control in which an alignment of each of the wheels 40 in the forward and backward direction with the tangent L1 of the orbit C (see 4 ) is reconciled; in the case where the actual inclination angle is larger than the allowable value, the calculation and control unit performs 80 a controller for correcting the steering angle θ of the wheel 40 , such as a Control for correcting the steering angle θ to the target steering angle θ ₀ , which is a predetermined appropriate steering angle.

In summary it can be said that the calculation and control unit 80 according to the second embodiment, executes a control in which it keeps the steering angle θ at zero degrees in the case where the actual load distribution nonuniformity degree and the actual inclination angle is equal to or less than a corresponding predetermined allowable value while performing a control in which it is the actual steering angle θ of the wheel 40 is corrected to the predetermined target steering angle θ ₀ in the case where both the actual load distribution nonuniformity degree and the actual inclination angle are larger than the corresponding predetermined allowable value. In addition, the calculation and control unit 80 is configured to perform a control of making the steering angle θ greater than the target steering angle θ ₀ by an amount larger than the difference between the actual load distribution nonuniformity degree and the allowable value of the load distribution nonuniformity degree or with an increase in the difference is increased between the actual inclination angle and the allowable value of the inclination angle. Alternatively, the calculation and control unit 80 be constructed to perform control of the steering angle θ on the basis of only one of the two differences: the difference between the actual load distribution nonuniformity degree and the allowable value of the load distribution nonuniformity degree; and the difference between the actual inclination angle and the allowable value of the inclination angle.

The above-explained control of the steering angle θ of the wheel 40 may be an excessive reduction in the turning radius r of the wheel 40 involve, as in the 4A and 4B is shown; in which case it is desirable to have the calculation and control unit 80 to make so that it performs a control in which the actual steering angle θ is made smaller than the target steering angle θ ₀ . For example, the presence or absence of the excessive reduction in the turning radius r may be determined on the basis of a detection signal received from the load sensor 74 and / or the tilt sensor 76 is issued. For example, the calculation and control unit 80 make a judgment that the turning radius r is excessively decreased when the tilt sensor 76 a reverse slope to that due to the increase of the turning radius r of the wheel 40 captured (for example, the slope of in 9B shown counterweight unit 90 ), or if the load sensor 74 Captures that one on one of the wheels 40 applied load disposed on a radially inner side with respect to the orbit C is less than a load applied to the other wheel 40 is applied, which is located on a radially outer side with respect to the orbit C. Incidentally, it is effective that at least either the memory section 85 for the permissible load distribution and / or the storage section 87 for the allowable inclination angle in this one allowable value for determining over the excessive reduction of the turning radius r in addition to the allowable value for determining an excessive increase of the turning radius r.

The inclination of the unitary body 35 the in 1 shown counterweight unit 30 can indirectly from a load distribution at the wheels 40 be derived. For example, the inclination of the unit body 35 also from a difference in the load between the two wheels 40 , which respectively on the inner and the outer side of the orbit C in 4A and 4B be derived in a radial direction.

Alternatively, the steering control device 101 be constructed such that: in the case where the load distribution nonuniformity of the wheels 40 the counterweight unit 30 or the inclination angle of the unit body 35 the counterweight unit 30 is equal to or less than a corresponding value of the allowable values, the steering control device 101 performs a control in which it brings the steering angle θ in accordance with the target steering angle θ _0, similar to the first embodiment; in the case where the load distribution nonuniformity degree or the inclination angle is larger than the corresponding value of the allowable values, the steering control device 101 performs a control in which they the steering angle θ of the wheel 40 greater than the target steering angle θ _{0 designed} by an amount of oversize.

The aforementioned control of the steering angle θ based on the load distribution nonuniformity degree of each of the wheels 40 allows reliable avoidance of non-uniformity of the respective loads acting on the respective wheels 40 due to the increase of the turning radius r, and the control of the steering angle θ on the basis of the inclination angle of the counterweight unit 30 allows reliable avoidance of the inclination of the counterweight unit 30 (especially their unitary body 35 ) due to the increase of the turning radius r. In addition, the calculation and control unit 80 , which is designed to perform the control on the basis of the actual load distribution nonuniformity degree and / or the actual inclination angle, are widely applied to various cranes substantially different from each other with respect to the model or the radius of the counterweight unit 30 differ in comparison to that crane, which is constructed so that the steering angle θ of the wheel 40 on the basis of only the pivoting direction of the upper pivoting body 20 is controlled.

Below is a steering control device 201 according to the third embodiment of the present invention with reference to 7 described. The steering control device 201 has a drive actuator 260 for a rotating driving of the wheels 40 by means of hydraulic pressure in addition to the components of the steering control device 101 (in the 6 shown) in the second embodiment. In conjunction with the drive actuator 260 a plurality of sensors are provided which generate respective detection signals input to the pan identification signal receiving section 81 are entered as signals for identifying the pivoting direction or the direction of rotation. The details of the steering control device 201 are described below.

In addition to the drive actuator 260 has the steering control device 201 a hydraulic pressure source 261 for supplying hydraulic pressure to the drive actuator 260 , a selector valve 262 that is between the hydraulic pressure source 261 and the drive actuator 260 is provided, and a hydraulic pressure signal sensor 263 ,

The selector valve 262 is designed so that it is between the operating modes of the drive actuator 260 on. The selector valve 262 has a plurality of positions to be selected, and the selected positions are switched in accordance with a hydraulic signal (pilot signal), which is in this for an operation instruction of the drive actuator 260 be entered. The selector valve 262 is operable to supply / not supply hydraulic pressure from the hydraulic pressure source 261 to the drive actuator 260 switches and the delivery directions of the hydraulic pressure, ie the Schaltantriebsrichtungen the wheels 40 through the drive actuator 260 switches by switching the selected position.

The drive actuator 260 is a hydraulic actuator that is adapted to be by the hydraulic pressure source 261 That is, for example, a hydraulic motor, supplied hydraulic pressure is driven, is formed and is on the unit body 35 the in 1 shown counterweight unit 30 attached. The drive actuator 260 rotates the wheels 40 in one direction, the selected position of the selector valve 262 corresponds to, and stops driving.

The rotary driving of the wheels 40 through the drive actuator 260 causes the counterweight unit 30 in a clockwise or counterclockwise direction in the plan view according to FIGS 4A and 4B drives (self-propelled). In the steering control device 201 is that in the drive actuator 260 according to 7 inputted operation instruction hydraulic signal as a swivel identification signal usable for identifying the pivoting direction of the upper swivel body 20 , In view of this, the hydraulic pressure signal sensor is 263 configured to receive the operating instruction hydraulic signal that is in the drive actuator 260 is input, converted into an electric signal and the resulting electric signal in the pan identification signal receiving section 81 as a pan identification signal indicative of an electrical signal for identifying the pan direction of the pan top body 20 is.

Like the hydraulic signal mentioned above, the delivery direction of the hydraulic pressure to the drive actuator 260 also usable as information for identifying the panning direction. Therefore, instead of (or in addition to) the hydraulic pressure signal sensor 263 a drive hydraulic pressure sensor 264 for detecting the delivery direction of the hydraulic pressure from the selector valve 262 to the drive actuator 260 , as shown by a dashed line with two points are applied. The drive hydraulic pressure sensor 264 is operable to provide an electrical signal to enable the pivoting direction of the upper pivoting body 20 is identified on the basis of a delivery direction of a drive hydraulic pressure to the drive actuator 260 and the resulting electrical signal to the pan identification signal receiving section 81 enters.

In the steering control apparatus according to the third embodiment, in the apparatus including the hydraulic pressure sensor such as the hydraulic pressure signal sensor 263 and / or the drive hydraulic pressure sensor 264 has the signals in the pan identification signal receiving section 81 entered within the counterweight unit 30 generated; therefore, there is no need to provide a new or additional signal line connecting the upper swivel body 20 with the counterweight unit 30 connects to the pivoting direction of the upper pivoting body 20 to identify. Thus, the present invention can be applied to an existing crane 10 applied without any changes except for the counterweight unit 30 ,

8th shows a steering control device 301 according to a fourth embodiment of the present invention. While at the in 7 shown steering control device 201 the hydraulic pressure to the steering actuator 50 from the hydraulic pressure source 51 which is different from the hydraulic pressure source 261 for the drive actuator 260 is different, is the hydraulic pressure source 261 for the drive actuator 260 at the in 8th shown steering control device 301 a double hydraulic pressure source for the steering actuator 50 , In other words, the drive hydraulic pressure for the drive actuator 20 parallel as a drive hydraulic pressure for the steering actuator 50 used. More specifically, the hydraulic pressure source 261 for the drive actuator 260 with the selector valve 52 for the steering actuator 50 through a pipe 351 connected.

In the in 8th shown steering control device 301 when starting to pan the in 1 shown upper swivel body 20 the drive actuator 260 and the steering actuator 50 activated and controlled so that an actual steering angle θ of each of the wheels 40 is matched with an appropriate steering angle such as the target steering angle θ ₀ . During this control, the selector valve 262 opened to the supply of hydraulic pressure from the hydraulic pressure source 261 to the drive actuator 260 continue while the selector valve 52 is closed to the supply of hydraulic pressure from the hydraulic pressure source 261 to the steering actuator 50 to stop.

In the steering control device 301 of the fourth embodiment, the hydraulic pressure source 261 for the drive actuator 260 as a hydraulic pressure source for driving the steering actuator 50 uses, the structure and operation of the steering control device 301 be simplified; alternatively, for example, by providing an operating instruction hydraulic pressure to the drive actuator 260 as a drive hydraulic pressure for the steering actuator 50 is also allowed to facilitate the construction and operation of the device. This use can be achieved, for example, by a line through which the hydraulic signal in the selector valve 262 is entered with the selector valve 52 through a pipe 351b connected by a dot-dash line with two dots in 8th is shown. Although this case, there is a possibility of insufficient power for driving the steering actuator 50 due to a low hydraulic pressure leading to the steering actuator 50 can be covered as compared with the fourth embodiment, the insufficient driving power can be covered, for example, as follows: by using an amplifier, one to the steering actuator 50 increased hydraulic pressure increases; by having a hydraulic cylinder with an enlarged cylinder bore size as the steering actuator 50 is applied; or by the steering actuator 50 and the wheels 40 be connected by an amplifier connection or the like.

It should be understood that the present invention is not limited to the above-described embodiments, but may include, for example, the following changes and modifications.

The electric circuit and the hydraulic circuit included in the steering control device can be variously changed to an extent in which the same effects can be obtained. For example, a hydraulic signal may be suitably replaced by an electrical signal. When the instruction hydraulic signal for the selector valve 262 in 8th is replaced by an electric signal, it becomes possible to input the electric signal into the pan identification signal receiving section 81 to enter directly while the sensors 263 and 264 be omitted.

1. (a) Ein Lenkwinkel θ, der einem maximalen Gewicht entspricht, das auf das Rad 40 gebracht wird, d. h. ein Gewicht des in 1 gezeigten Einheitskörpers 35, kann in dem Solllenkwinkel-Speicherabschnitt 83 als der Solllenkwinkel θ₀ gespeichert werden.
2. (b) Es ist außerdem möglich, eine Höhe einer auf das Rad 40 aufgebrachten Last zu erfassen und den Lenkwinkel θ gemäß der erfassten Höhe zu steuern. Die auf das Rad 40 aufgebrachte Last kann beispielsweise durch eine Lastzelle für ein Erfassen einer Spannung des in 1 gezeigten Hängeseils 31 oder den in 6 gezeigten Lastsensor 74 erfasst werden.
3. (c) Der Solllenkwinkel θ₀, der von dem in den 4A und 4B gezeigten Drehradius abhängt, kann in dem Solllenkwinkel-Speicherabschnitt 83 in der Form beispielsweise einer Tabelle oder einer Zuordnung gespeichert werden.
4. (d) Es ist außerdem möglich, den Drehradius r zum Steuern des Lenkwinkels θ gemäß dem erfassten Drehradius zu erfassen. Der Drehradius r kann beispielsweise durch einen Längensensor zum Erfassen einer Länge des in 1 gezeigten Einheitskörperverbindungselementes 32 erfasst werden oder kann beispielsweise auf der Basis eines Anhebe/Absenkwinkels des in 1 gezeigten ersten Masts 22 berechnet werden.
5. (e) Der Solllenkwinkel θ₀ kann in Abhängigkeit von einer Geschwindigkeit einer Drehfahrt (beispielsweise eine maximale Geschwindigkeit oder eine durchschnittliche Geschwindigkeit während einer Drehfahrt) der in 1 gezeigten Gegengewichtseinheit 30 vorbestimmt sein.
6. (f) Es ist außerdem möglich, eine Drehzahl des Rades 40 und/oder eine Schwenkgeschwindigkeit des oberen Schwenkkörpers 20 durch einen Sensor zu erfassen und den Lenkwinkel θ gemäß dem Erfassungsergebnis zu steuern.
7. (g) Es ist außerdem möglich, einen Innendruck des Rades 40 zu erfassen und den Lenkwinkel θ gemäß der berechneten Bodenkontaktlänge Lc des in 5B gezeigten Rades 40 auf der Basis des Erfassungsergebnisses zu steuern.

The appropriate steering angle θ of the wheel 40 who by the in 3 shown calculation and control unit 80 can be controlled, for example, can be set in the following manner.

1. (a) A steering angle θ corresponding to a maximum weight applied to the wheel 40 is brought, ie a weight of in 1 shown unit body 35 , may be in the target steering angle storage section 83 as the target steering angle θ ₀ are stored.
2. (b) It is also possible to set a height one on the wheel 40 to detect applied load and to control the steering angle θ according to the detected height. The on the wheel 40 applied load may be, for example, by a load cell for detecting a voltage of in 1 shown hanging rope 31 or the in 6 shown load sensor 74 be recorded.
3. (c) The target steering angle θ ₀ , that of the in the 4A and 4B in the target steering angle storage section 83 be stored in the form of, for example, a table or assignment.
4. (d) It is also possible to detect the turning radius r for controlling the steering angle θ according to the detected turning radius. The turning radius r can be adjusted, for example, by a length sensor for detecting a length of the in 1 shown unit body connecting element 32 can be detected or, for example, on the basis of a lifting / lowering angle of the in 1 shown first mast 22 be calculated.
5. (e) The target steering angle θ ₀ may vary depending on a speed of a turning travel (for example, a maximum speed or an average speed during a turning travel) of the in 1 shown counterweight unit 30 be predetermined.
6. (f) It is also possible to have a rotational speed of the wheel 40 and / or a swivel speed of the upper swivel body 20 to detect by a sensor and to control the steering angle θ according to the detection result.
7. (g) It is also possible to have an internal pressure of the wheel 40 to detect and the steering angle θ according to the calculated ground contact length Lc of in 5B shown wheel 40 on the basis of the detection result.

As described above, according to the present invention, there is provided a crane equipped with a counterweight unit having a plurality of wheels capable of running on the ground in a rotating direction, the crane being provided with a counterweight is able to avoid increasing the swing radius of the wheels to improve the operating efficiency of the crane. The created crane comprises: a lower body; an upper pivot body mounted on the lower body so as to be pivotable; a counterweight unit including a plurality of wheels each capable of rolling on the ground and having a variable steering angle, the counterweight unit being capable of running on the ground with respective rolling movements of the wheels in a rotational direction equal to a pivoting direction of the upper Swing body is, in a state in which it depends on the upper swivel body; a steering actuator adapted to rotate the wheels about a steering axis of rotation to change their steering angle; and a steering control device for controlling the operation of the steering actuator. The steering control device has a swivel identification signal receiving section that receives a swivel identification signal to enable a swivel direction of the upper swivel body to be identified, and an actuator operating section operates the steering actuator so that the wheels orbit toward the inside of a tangent line on the steering swivel center axis of the wheels the counterweight unit are aligned based on the pivoting direction identified by the swivel identification signal.

The steering control apparatus of the present invention thus aligning each of the wheels of the counterweight unit with the inner side of the tangent line to the orbit of the wheels can avoid an increase in the radius of rotation of the wheel during the rotation of the counterweight unit, thereby enabling the efficiency of the crane operations to be improved becomes.

In a preferred embodiment of the present invention, the steering control device further has a target steering angle storage portion storing therein a target steering angle of each of the wheels, wherein the target steering angle is predetermined according to the swinging direction of the upper swing body, the actuator operating portion operating the steering actuator so that the target steering angle Steering angle of the wheel is brought into agreement with the stored in the target steering angle storage section target steering angle. In this embodiment, the control of the operation of the steering actuator allows the steering angle of the wheel to be matched with the predetermined target steering angle, thereby simplifying the calculation and control operations of the steering control device as compared with the case where the target steering angle during the turning operation is on one Real-time basis is calculated.

Preferably, the steering control apparatus further comprises: a load signal receiving section that receives a load signal that is a signal indicating information about the respective loads applied to the wheels; and an allowable load sharing storage section storing therein a predetermined allowable load distribution nonuniformity indicative of a degree of nonuniformity between the respective loads applied to the wheels, the actuator operating section operable to control the operation of the steering actuator according to a difference between a load distribution nonuniformity degree derived from the load signal received by the load signal receiving section and the allowable value of the load distribution nonuniformity degree stored in the allowable load distribution storage section. The steering control device controls the steering angle of each of the wheels on the basis of the load distribution nonuniformity increasing in response to an increase in the turning radius of the wheel, thereby executing an appropriate steering control for avoiding the increase of the turning radius.

More specifically, it is preferable that the steering control device further has, for example, a target steering angle storage section storing therein a target steering angle of each of the wheels predetermined according to the swinging direction of the upper swing body, the actuator operating section executing a control in which the steering angle of each of the wheels is kept at zero when the load distribution nonuniformity derived from the load signal received by the load signal receiving section is equal to or less than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing memory section during Actuator operating section, the steering actuator is operated so that the steering angle of each of the wheels is equal to or greater than the target steering angle is formed in the Solllenkwinkel- Memory portion is stored when the load distribution nonuniformity, which is derived from the load signal received by the load signal receiving section, is greater than the allowable value of the load distribution nonuniformity degree, which is stored in the permissible load distribution memory section.

In this case, the actuator operating section may be configured such that, when the load distribution nonuniformity derived from the load signal received by the load signal receiving section is greater than the allowable value of the load distribution nonuniformity degree stored in the allowable load distribution storage section, the actuator operating section Steering actuator is operated so that the steering angle of each of the wheels greater than the target steering angle is designed by an amount of the difference between the load distribution nonuniformity derived from the load signal and the allowable value of the load distribution nonuniformity degree stored in the allowable load distribution memory section is, corresponds. This makes it possible to realize a steering control that is even more suitable for an actual load distribution nonuniformity.

Alternatively, it is also preferable that: the steering control device further has a target steering angle storage portion that stores therein a target steering angle of each of the wheels that is predetermined according to the swinging direction of the upper swing body; and wherein the actuator operating section operates the steering actuator so as to match the steering angle of each of the wheels with the target steering angle stored in the target steering angle storage section when the load distribution nonuniformity derived from the load signal received by the load signal receiving section is equal to or while the actuator operating portion operates the steering actuator so as to operate the steering actuator to increase the steering angle of each of the wheels by greater than the target steering angle by a torque value less than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing section Amount of the difference between the load distribution nonuniformity degree derived from the load signal and the allowable value of the load distribution nonuniformity degree stored in the allowable load storage section when the load distribution nonuniformity derived from the load signal received by the load signal receiving section is greater than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing memory section.

This also enables realization of a control suitable for an actual load distribution nonuniformity and effective in preventing an increase in the radius of rotation of the wheel.

It is also preferable that the steering control device further comprises: a pitch angle signal receiving section that receives a pitch angle signal that is a signal indicating information about a pitch angle of the counterweight unit with respect to a direction of a turning radius of the counterweight unit; and an allowable inclination angle storage section storing therein a predetermined permissible value of the inclination angle, the actuator operating section specifying the operation of the steering actuator according to a difference between an inclination angle derived from the inclination angle received by the inclination angle signal receiving section and the allowable value of the inclination angle stored in the allowable inclination angle storage section. This steering control device adapted to control the steering angle of each of the wheels based on the inclination angle of the counterweight unit with respect to a direction of the turning radius that increases in response to an increase in the turning radius of the wheel may execute a steering control is suitable for avoiding an increase of the turning radius.

More specifically, it is preferable that the steering control device further has, for example, a target steering angle storage section storing therein a target steering angle for each of the wheels that is predetermined according to the swinging motion of the upper swing body, wherein: the actuator operating section executes a control in which the steering angle is kept at zero by each of the wheels when the inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section is equal to or less than the allowable value of the inclination angle stored in the allowable inclination angle storage section; and the actuator operation section operates the steering actuator such that the steering angle of each of the wheels is made equal to or greater than the target steering angle stored in the target steering angle storage section when the inclination angle derived from the tilting angle signal received by the inclination angle signal receiving section is greater than the allowable value of the inclination angle stored in the allowable inclination angle storage section.

In this case, the actuator operating section may be configured so that when the inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section is larger than the allowable value of the inclination angle stored in the allowable inclination angle storage section, the actuator operation section operates the steering actuator so as to make the steering angle of each of the wheels greater than the target steering angle by an amount equal to the difference between the inclination angle derived from the inclination angle signal and the allowable value of the inclination angle included in the storage section for the permissible angle of inclination is stored corresponds to. This also makes it possible to realize a control suitable for an actual inclination angle and effective in avoiding an increase in the rotational radius of the wheel.

Alternatively, it is also preferable that: the steering control device further has a target steering angle storage portion that stores therein a target steering angle of each of the wheels that is predetermined according to the swinging direction of the upper swing body; wherein the actuator operation section operates the steering actuator so that the steering angle of each of the wheels coincides with the target steering angle stored in the target steering angle storage section as the inclination angle derived from the tilting angle signal received by the tilting angle signal receiving section becomes equal is or less than the allowable value of the inclination angle stored in the allowable inclination angle storage section; and the actuator operation section operates the steering actuator so as to make the steering angle of each of the wheels greater than the target steering angle by an amount equal to the difference between the inclination angle derived from the inclination angle signal and the allowable value of the inclination angle included in the storage section is stored for the allowable inclination angle, when the inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section is greater than the allowable value of the inclination angle stored in the allowable inclination angle storage section. This also enables a control suitable for an actual inclination angle, which is effective in avoiding an increase in the rotational radius of the wheel.

In the present invention, the signal input to the swivel identification signal receiving section of the steering control device may be an electric signal output from the upper swivel body.

Further, when the crane has a drive actuator for rotatably driving the wheels and a hydraulic pressure sensor for generating a signal based on a hydraulic pressure serving as an operation instruction or a drive force for the drive actuator, the electric signal generated by the hydraulic pressure sensor may be generated is input to the swivel identification signal receiving section of the steering control device. When the crane further has a drive actuator for rotatably driving the wheels and a hydraulic pressure source for operating the drive actuator, the hydraulic pressure source may be doubled to a hydraulic pressure source for actuating the steering actuator. This makes it possible to simplify the structure and operation of the steering control device.

Similarly, in the case where the crane further includes a drive actuator that operates to rotationally drive the wheels by receiving an input signal of a hydraulic signal, the hydraulic signal may be applied as a hydraulic pressure to operate the steering actuator. This makes it possible to simplify the structure and operation of the steering control device.

Although the present invention has been described in detail by way of example with reference to the accompanying drawings, it should be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, such modifications and changes are intended to be included, unless such modifications and changes depart from the scope of the present invention defined herein.

There is disclosed a crane comprising: a lower body; an upper swing body, a counterweight unit having a plurality of wheels that run on the ground in a rotational direction that is equal to a swing direction of the upper swing body while suspended from the upper swing body; a steering actuator for rotating each of the wheels about a steering rotational center axis to change the rotational angle; and a steering control device for controlling the steering actuator. The steering control apparatus comprises: a pan identification signal receiving section that receives a pan identification signal for identifying the pan direction of the pan top body; and an actuator operating section that operates the steering actuator so that each of the wheels is aligned with the inside of the tangent line with an orbit of the wheel on the steering axis of rotation on the basis of the identified pivot direction identified by the pan identification signal.

Claims (14)

Crane (10) with: a lower body (15); an upper pivot body (20) mounted on the lower body (15) so as to be pivotable; a counterweight unit (30) having a plurality of wheels (40) each capable of rolling on the ground (G) and having a variable steering angle (θ), the counterweight unit (30) being able to roll on the ground (G) with respective rolling movements of the wheels (40) in a rotational direction which is equal to a pivoting direction of the upper pivoting body (20) to drive in a state in which it depends from the upper pivoting body (20); a steering actuator (50) adapted to rotate the wheels (40) about a steering axis of rotation to change their steering angle (θ); and a steering control device (80; 201) for controlling an operation of said steering actuator (50), said steering control device (80; 201) comprising a swivel identification signal receiving section (81) receiving a swivel identification signal for identifying a swivel direction of said upper swivel body (20). and having an actuator operating portion (80a) that operates the steering actuator (50) based on an orbit of the counterweight unit (30) and the swivel direction identified by the swivel identification signal so as to make a line along the traveling direction of the wheels (40) is that it is inclined inwardly to a tangent line, which is arranged on the Lenkdrehmittelachse of the wheels (40), wherein the tangent line which is tangential to the orbit of the rotating counterweight unit (30), when the upper swivel body (20) pivots so that driving the counterweight unit (30) in the direction of rotation involved i st. Crane (10) according to Claim 1 wherein the steering control device (80) further has a target steering angle storage section (83) storing therein a target steering angle (θ ₀ ) of each of the wheels (40) predetermined according to the swinging direction of the upper swing body (20), and wherein the actuator operation section (80a) operates the steering actuator (50) to make the steering angle (θ) of the wheel (40) coincident with the target steering angle (θ ₀ ) stored in the target steering angle storage section (83). Crane (10) according to Claim 1 wherein the steering control device (80; 201) further comprises: a load signal receiving section (84) receiving a load signal that is a signal indicating information about respective loads applied to the wheels (40); and a permissible load distribution storage section (85) storing therein a predetermined allowable value of a load distribution nonuniformity indicative of a degree of nonuniformity among the respective loads applied to the wheels (40), and wherein the actuator operating section controls the operation of the steering actuator (FIG. 50) is controlled according to a difference between a load distribution nonuniformity derived from the load signal received by the load signal receiving section (84) and the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing section (85). Crane (10) according to Claim 3 wherein the steering control device (80) further has a target steering angle storage portion (83) storing therein a target steering angle (θ ₀ ) of each of the wheels (40) predetermined according to the swinging direction of the upper swing body (20), and wherein the actuator operation section (80a) performs a control in which the steering angle (θ) of each of the wheels (40) is kept zero when the load distribution nonuniformity derived from the load signal received by the load signal receiving section (84) equals while the actuator operation portion (80a) operates the steering actuator (50) so that the steering angle (θ) of each of the wheels is less than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing memory portion (85) (40) is equal to or greater than the target steering angle (θ ₀ ) stored in the target steering angle storage section rt is designed when the load distribution nonuniformity derived from the load signal received by the load signal receiving section (84) is greater than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing section (85). Crane (10) according to Claim 3 wherein, when the load distribution nonuniformity derived from the load signal received by the load signal receiving section (84) is greater than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing memory section (85), the actuator operating section (80a) the steering actuator (50) is operated so that the steering angle (θ) of each of the wheels (40) is made larger than the target steering angle (θ ₀ ) by an amount equal to the difference between the load distribution nonuniformity derived from the load signal and the allowable value of the load distribution nonuniformity degree stored in the allowable load distribution storage section (85). Crane (10) according to Claim 1 wherein the steering control device (80) further comprises Target steering angle storage portion (83) having therein a target steering angle (θ ₀ ) of each of the wheels (40) predetermined according to the swinging direction of the upper swing body (20), and wherein the actuator operating portion (80a) drives the steering actuator (50 ) is operated so that the steering angle (θ) of each of the wheels (40) is made coincident with the target steering angle (θ ₀ ) stored in the target steering angle storage section (83) when the load distribution nonuniformity from that detected by the load signal receiving section (84) is equal to or less than the allowable value of the load distribution nonuniformity degree stored in the allowable load sharing memory section (85) and which operates the steering actuator (50) such that the actuator operating section (80a) Steering angle (θ) of each of the wheels (40) greater than the target steering angle (θ ₀ ) designed by an amount is the difference between the load distribution nonuniformity degree derived from the load signal and the allowable value of the load distribution nonuniformity degree stored in the allowable load distribution storage section (85) when the load distribution nonuniformity degree different from that indicated by the load signal. Receive section (84) received load signal is greater than the allowable value of the load distribution nonuniformity degree, which is stored in the storage section (85) for the allowable load distribution. Crane (10) according to Claim 1 wherein the steering control device (80) further comprises: an inclination angle signal receiving section (86) that receives an inclination angle signal that is a signal indicative of an inclination angle of the counterweight unit with respect to a direction of a rotational radius of the counterweight unit; and an allowable inclination angle storage section (87) storing therein a predetermined allowable value of the inclination angle, and wherein the actuator operation section (80a) controls the operation of the steering actuator (50) according to a difference between the inclination angle different from that caused by the inclination angle signal. Receiving section (86) received tilt angle signal is derived, and the permissible value of the inclination angle, which is stored in the storage section (87) for the allowable inclination angle controls. Crane (10) according to Claim 6 wherein the steering control device (80) further has a target steering angle storage portion (83) storing therein a target steering angle (θ ₀ ) of each of the wheels (40), the target steering angle (θ ₀ ) corresponding to the swinging direction of the upper swing body (FIG. 20) is predetermined, and wherein the actuator operation section (80a) executes a control in which the steering angle (θ) of each of the wheels (40) is kept zero when the inclination angle different from that obtained by the inclination angle signal receiving section (86) is received, equal to or less than the allowable value of the inclination angle stored in the allowable inclination angle storage section (87), and wherein the actuator operating section operates the steering actuator (50) so that the steering angle (θ) of making each of the wheels (40) equal to or larger than the target steering angle (θ ₀ ) stored in the target steering angle storage section t, when the inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section (86) becomes larger than the allowable value of the inclination angle stored in the allowable inclination angle storage section (87). Crane (10) according to Claim 7 wherein, when the inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section (86) is larger than the allowable value of the inclination angle stored in the allowable inclination angle storage section (87), the actuator operation section (14) 80a) operates the steering actuator (50) so as to make the steering angle (θ) of each of the wheels (40) greater than the target steering angle (θ ₀ ) by an amount equal to the difference between the inclination angle and the inclination angle signal and the permissible value of the inclination angle stored in the allowable inclination angle storage section (87). Crane (10) according to Claim 6 wherein the steering control device (80) further has a target steering angle storage portion (83) storing therein a target steering angle (θ ₀ ) of each of the wheels (40) predetermined according to the swinging direction of the upper swing body (20), and wherein the actuator operation section (80a) operates the steering actuator (50) so as to make the steering angle (θ) of each of the wheels (40) coincident with the target steering angle (θ ₀ ) stored in the target steering angle storage section (83) The inclination angle derived from the inclination angle signal received by the inclination angle signal receiving section (86) is equal to or less than the allowable value of the inclination angle stored in the allowable inclination angle storage section (87) while the actuator operation section (80a ) operates the steering actuator (50) so that the steering angle (θ) of each of the wheels (40) is greater than the target steering angle (θ ₀ ) is designed by an amount corresponding to the difference between the inclination angle derived from the inclination angle signal and the allowable value of the inclination angle stored in the allowable inclination angle storage section (87) when the inclination angle which is derived from the tilt angle signal received by the tilt angle signal receiving section (86) is larger than the allowable value of the tilt angle stored in the allowable tilt angle storage section (87). Crane (10) according to Claim 1 wherein the signal input to the swivel identification signal receiving section (81) of the steering control device (80) is an electrical signal output from the upper swivel body (20). Crane (10) according to Claim 1 further comprising a drive actuator (260) for rotatably driving the wheels (40) and a hydraulic pressure sensor (264) for generating an electrical signal based on a hydraulic pressure serving as an operation instruction or a drive force for the drive actuator (260) wherein the signal input to the swivel identification signal receiving section (81) of the steering control device (201) is an electrical signal generated by the hydraulic pressure sensor (264). Crane (10) according to Claim 1 further comprising a drive actuator (260) for rotationally driving the wheels (40) and a hydraulic pressure source (261) for operating the drive actuator (260), the hydraulic pressure source (261) duplicating a hydraulic pressure source to actuate the steering actuator (50) ). Crane (10) according to Claim 1 further comprising a drive actuator (260) rotationally driving the wheels (40) by receiving an input signal of a hydraulic signal, the hydraulic signal being used as a hydraulic pressure to operate the steering actuator (50).

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